Hey I have a cheap camcorder that runs on AA's but I want to put it on a lithium battery. What I want to use is just the standard battery out of an old phone 3.2v, I'd like to use these because I have a huge surplus of them. I have pretty much no knowledge of electrical circuits and so I need of bit of help. I know two AA's is 3v and any lithium battery is 3.2v, how could I step the battery down to 3v?

I have to build a pack to run my portable N64. I have some experience building with NiMh and NiCad, but I havent built a li-ion yet. Ive done my research but would like some feedback before I start building. Parts 18650's - 3.7V 3600mAh ea 7.4V PCM for 18650 Li-Ion/ LiPo 7.4V Li-ion/LiPo charger at 1.2 Ah Plan Either to build a 2S2P pack or a 2S4P pack. Currently the N64, 7" TFT LCD, Controller, and Audio amp w/ 2x 8Ohm speakers is consuming just over 1A from what i can tell. its running off of a perfboard w/ regulator and rail, thats hooked up to a universal transformer that is set to 7.5V 1A. Everything works but when I turn the volume up it cuts off and then powers back on. I dont know any other way to find out the over all power consumption. I cant just look up all the specs because the LCD is from china and i dont have any specs. Anyway, back to my plan. obviousely I want as much run time as i can get out of it with out compromising weight and space. all componants of the portable can run off of 7.4V or lower, to include the lcd even though its rated at 12V. it can run as loas 6.5V. I have been debating between the 2S2P which should yeild 7.4V 7.2 Ah, and give me a runtime, some where in the ball park of 4 hours. or a 2S4P which should yield 7.4V 14.4 Ah. It would only be slightly more space and provide approximately 8 Hours+ Thats if I am even calculating everything right Ok, Regardless of whether i run a 2S2P or 2S4P the connections to the Protection Circuit will be the same, Right? Pos --> B+ Neg --> B- + to - ( Between Series connection) --> B1 or BM I understand that Li-Ion are safer when it comes to balancing then LiPo, but is this right? having 2 parallel cells or 4 parallel cells connected with the only balance connection between the series. I just want it to be safe. Next is the charging. I bought a cheap smart charger for 7.4V 1.2A output. Will it matter whether i build the 2S2P or 2S4P, or will it work for both. I know it will obviousely take twice as much time to charge with the bigger pack, but is their a max number of individual cells that a PCB can handle, or does it only matter the overall voltage? I also Included in my diagrahm a setup for a DPDT switch to change between pack powered, wall powered and battery charging. I want it to have an "ON" and "OFF" setting. while off, pack is disconnected and if wall charger is plugged in, it will charge the pack. while in the "ON" position, pack will power the device, but if wall charger is plugged in, then it will run off that. Can I even use a wall charger for the Li-Ion pack to power the device, or will it not work.??

hello, i extracted some lithium metal from some new lithium batteries i bought at a second hand shop really cheaply . ive extracted the metal from one, but now, after placing it under vegetable oil to store, then putting in water, the vegetable oil works too well seperating the lithium form the water, making small lithium combustion reactions very difficult and i really want to show my friends the marvels of lithium on water, so i want to know, is it safe to store lithium in methylated spirits, or some other hydrocarbon that will evaporate away really fast , and not inhibit the lithium's reaction with water, like canola oil does? clean lithium usually combusts when i put it in water , and the reaction is quite fast. but when i put oily lithium in water, the same does not happen, the reaction is slow, and no combustion occurs unless i use my jet lighter.

I picked up 4 Canon NB-4L batteries for 50p each, thinking that for the price they might be worth having. However, I don't have a charger - any help with this? I've got power and electronics and stuff. 3.7V 760mAh (Li-ion)

Hello! I bought a li-on battery ( http://m.ebay.de/itm/281697770691?varId=580703135130) and it has this little switch. I want to build a boombox and dont want to open it everytime to turn it on or off. I also dont want to rip the switch appart because i sind want to destroy the batterypack. Can i leave it turned on and place a switch between the circuit and the batterypack? Or will i destroy it if i leave it on all the time?

Hi all, I have a problem with the motor of the cordless drill. I converted my cordless drill from Ni-Cd battery to Li-ion battery 12v6 using the protected PCB as this image: http://www.ultest.com/shop/image/cache/catalog/Power-Modules/HX-3S-A01-1-500x500.jpg. After connecting the 3 cells Li-ion battery to PCB, I measured the voltage at P+ and P- is 12v. So the connection between the battery and PCB is correct! Try to connect P+ and P- (from PCB) to the positive and negative terminals of the motor, then the PCB cut-off voltage at the output pin. The reason is the 2 terminals of the motor is connected (using the Digital Multimeter to check). How to resolve this problem with the motor working properly? Thanks. Sy Do

I know that Nicad batteries can be damaged from being left in the car in sub freezing temperatures. Is this also true of lithium batteries? I'm in a northern climate where we experience below zero temperatures so I need to know if I have to keep bringing my lithium battery packs inside every time I park the car.

Hello everyone, I have been looking to source a motor very similar to the motors used in the newer 80v Lithium lawn mowers. Does anyone have any information on them? Do they use direct drive to the blade or belt etc? Thank you! Nuker-

Hey all Looking at doing a lithium battery build but trying to cut down on soldering or spot welding. My idea is to use a stack of 3 18650 batteries in series pushed inside a piece of PVC pipe, thus making a 12V tube and then having multiples joined together to make the final battery Is there any reason why people mostly use a set of batteries is paralel then series?

Hello Everyone! I am planning to make a rear bike light, which has rechargeable batteries through USB. I then decided to use Lithium Ion Batteries for it. But the problem is that I dont know what parts I need. It should be able to light up 4 COB LEDs (Each rated 12V, photo given) Till now, after looking at several other instructables, I am able to say that: 1. It needs a steup transformer from 5V TO 12 V - TP4056 (https://www.amazon.in/TP4056-lithium-Battery-Charging-Charger/dp/B00JQ2VG1A/ref=sr_1_8?ie=UTF8&qid;=1505148914&sr;=8-8&keywords;=lithiumion+batteries) or https://www.adafruit.com/product/259 2. It needs some sort of protection like: http://www.batteryspace.com/PCB-for-11.1V-Li-Ion-Battery-Pack-4.0A-limit-----PCM-L03S04-559.aspx 3. Also do can I allign three 3.7V Lithium Ion Batteries to make 11.1V? Please help me out Thanks!

Hello, I'm looking for a rechargeable battery for a project and I'm not having any luck finding a suitable one. Here's what I need: The battery will need to be between 12 - 18v with between 1-2 amp. This will be powering a set of speakers, so not really sure what type of amp hours I need. The battery will need to fit into a tin lunch box. An idea I had was to use a 12 or 18v battery for Power Tools - not sure if it will work though. I also found this, http://www.altex.com/12V-Lithium-Ion-Rechargeable-Battery-Set-LBP-124500-P150057.aspx not sure if it is powerful enough though. Any thoughts/ideas is appreciated.

1 st question: i have a 7.4v 2200mA li ion battery. my ip camera takes 5v 2amps what color resistor should i use and how many ohms? 2nd quesiton: i have a class 2 battery charger 12 volts 300mA is it good to charge my 7.4v li ion battery?

I am looking for a few batteries for my flashlight. i have one the LC 18650 but it will only lash a few days of use. OK, i do want a high quality 3A battery (for 1000 LM from my light) so one that that supports the current. i prefer one with a safety circuit in it, one that holds at least 2200 MAh, ok, i shop for that, but what is the difference between: LIR 18650, LC 18650 (the one i have) (i think LC stands for "low current drain"), GTL 18650, TR 18650, AW 18650, (i know this offers 5A, but its expensive and rare.) BRC 18650, XSL 18650, TRC 18650, i know the AW battery offers 5A max.

I have a 7.4V lithium polymer battery (http://www.all-battery.com/74volt-6000mahli-polypackwithpcb31185.aspx) and an 8.4V smart charger (http://www.all-battery.com/universalsmartchargerforli-ionpolymerbatterypack37v-148v1-4cells.aspx). The issue is that I need to power a device that needs 6V. If I put a voltage regulator in line with the battery leads I'm sure it'll work, but then how do I charge the battery with that charger, as the regulator will also reduce the 8.4V the battery needs for charging? Maybe by introducing some kind of "bare metal tap" upstream of the regulator, so when I plug in the charger it bypasses the regulator and wires straight to the battery? (see the attached illustration) Would this work? Or should I do something else?

If I bought 2 rechargeable lithium polymer batteries for a cell phone, but only needed one for now, could I store the unused battery until the first battery quit charging (and was garbage)? If the above question makes ZERO SENSE, let me try explaining it another way: Ok, you have this fancy gadget that you want to keep functioning for many years. Eventually, the battery inside won't be able to take a charge, and the battery will be obsolete and no longer sold. Would it make sense to buy extra batteries ('stock up') and store them for a time when the original battery went bunk; would the stored batteries be like brand new after many years (these batteries would have never been charged before.. they would be still originally packaged)? Hope that actually makes sense :D -Neph

I have an older (dell latitude c400) that works great, its tiny and weights only about 4 pounds. I got it 2nd hand about a year ago, ever since I got it the battery shows no charge even when the laptop is plugged 24/7.
Is there a way I can "zap" the battery or something like that?? I've seen instructables about zpping nicad batteries but nothing about lithium ion ones...
Any and all help will be appreciated.

So I have an Idea for a charger for a portable computer. It will be solar powered, and charge li-ion batteries. My question is how could I simultaneously charge batteries and power the computer at the same time. No schematics are needed, just a quick written answer. Thanks!

Hi, I'm a first time DIY-er and would like to build a useful, long lasting battery pack for my *new* laptop (late summer). I'm 17, and this would be a perfect project for me to finish in the next few months. I'll be working with my dad and asking my physics teacher, who seems very all-knowing, for advice. My teacher understands electricity and batteries better than anyone else locally and is leading our STEM team, of which I am a member and need this experience. Keep in mind that I'm not just doing this to have a (much needed) battery pack for my laptop. I got most of my information from here and will most likely be purchasing new batteries. As far as the housing of the components, I have a hard plastic, 10+ year old lightly used blue lego container in the shape of a kid-sized briefcase. Case: Old blue lego carrying case, 11” x 7.5”(9 including curved front) x 3.5” Insulation tape Batteries: (x4) Battery holders: (x4) PCB: (protected voltage is higher, balance charger required) Balance Charger: Fuel Gauge: DC port: Wire terminals (for organization) Balance charge cords: Optional inverter: I heard about these being inefficient, so I'm not sure about it. Please inform me if there are any other parts that I'll need or if I've left out any information. Also Inform me if everything I'll need for a lithium battery pack is on this list. P.S. The case was chosen based on the fact that it will fit in my backpack with my books and looks much less alarming and more like a DIY battery than a black box or briefcase. especially with the fuel gauge and plugged in laptop.

Something odd happened today. I went to use my Skyray king flashlight, but the output was very dim. I pulled the batteries out, 3 were at 2.7V, and one of them was completely dead. IDK how they discharged as I charged them not too long ago. They have protection PCBs in them so that is the first thing I suspected that tripped in the dead one. Sticking that one on the charger did not reset the protection PCB. So I pulled the insulation of the dead battery, However it is the battery itself has failed high impedance / open circuit. Even bypassing the protection PCB, I still only measure 0.001ish volt measured across it (the real measurement varies a large amount) and only uA of current short circuit. I applied 4-40V to it and measured no current flowing into the cell. Certainly open-circuit. I just thought this was peculiar, what is going on with this cell? I figured if it discharges all the way the internal resistance will go up a little, but to the point of becoming a complete open circuit!!! It is possible that a internal bond broke?

I was wondering.... The protection circuit for li ion cells in phones; is it a sort of regulator for the battery when charging? Or does it just stop the cell from being drained too far? I was wondering if I could use the circuitry from the prismatic li ions found in mobile phones for a 18650 battery....will the difference in capacity be a problem?

I am making a wind turbine charge my cell phone. my design will use a hand made wind turbine using an electric motor. hooked upto a 5v voltage regulator. with some capacitors. if it is putting out 5v i know it will charge right? i heard of batteries messing up. i will constantly monitor the phone too see when it is charged..according to my phones battery indicator

I have a 7.4V rechargeable battery and I'm wondering what voltage I should be charging it with. would 9V work? Are there any general guidelines for recharging batteries? Specs: 7.4V 1400 mAh Lithium-ion Was originally used in a NXT LEGO robot. Thanks! Ryan

I’m looking to build a custom battery back from LFE / LiFePO4 batteries or possibly Li Ion. I need someone familiar with power management and charge management circuitry in relation to these batteries. I’m looking to have someone to build a prototype for me, and consult me on modifications. Preferably I’d like to find someone around the Chicago – Milwaukee area who I can work face-to-face with, although phone-based work would also work. I am of course willing to pay for services rendered.

So I was just wondering, what basic guid lines do you have to follow when making a battery charger for say a lithium-ion battery? How many volts do I need to supply to it? Do I need any protection diodes? How would I keep it from charging to fast, or trying to charge the charger? Thanks!

I have an idea to make a power bank that can charge my laptop, but I don't know how to make it. The adapter input is 100v-220v~ 1.83A and the output is 19.7v ~3.87A Please, I really want to make it real and I think many people have the same idea, so I need your help.

I am charging my cellphone. its an android. the charger for it says the output is 5v 700 mA. i am using a wind turbine or solar panel or both connected to a 5v regulator. and some capacitors. should work right? i will keep a close eye on the phone checking the phones battery indicator to see when it is completely charged to avoid overcharge

Has anyone used a very small low voltage cut off (LVCO) circuit on a lithium polymer battery? I found a nice collection of lithium polymer cells in a 'dead' laptop battery. Thing is, I don't want to be careful about over draining them and they don't seem to have a low voltage cut off circuit in the individual cells. Sparkfun sells batteries with a teeny LVCO system built into the cell package like this: http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/BatteryProtection.pdf What would be a reliable source of similar reliable boards that protect from over discharge?

Call me stupid, because I am, but I was extracting lithium from an old phone battery when it begun sparking and smoking a lot, I dumped it in some vegetable oil seconds after it started but it's vessel is still warm, and I'm worried it'll ignite, help me?

What resistors do I change in this circuit to make it go red at <3.2V and green at >3.2V ? It is a battery monitor that uses op-amp, 2.5v voltage reference diode, and a 2-pin bi-color LED. The trimpot adjusts the voltage at which the colour changes. http://i48.tinypic.com/28qtb3l.gif

I want to get these 12v solar battery chargers they come with alligator clamps to hook to the battery. i want to get enough for around 150 volts so how would i hook the solar panels in series, and do i need a controller for each battery? and how would i rig that up and how can I get it going into all the 12 volt batteries without any damage to the batteries etc. And can this be done for less than $400 if the solar panels are $30 each and the batteries are $14 each. THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! oh and could you give me links for all the stuff I'm gonna be buying. THANKS!!!!

I plan to make a portable audio system with 4 speakers and a subwoofer which are driven by a 12v TDA2030A 2.1 Amplifier. Everything is already packed in a small enclosure (approx. 30x15x30cm) and works fine so far. At the moment the amp gets it's signal from a 3.5mm audio jack and the power is provided via a 12v 1.5Ah wall wart. That's what I have for now. But that's not really portable right? So to complete my project I want to add 2 more things - a bluetooth receiver powered with 5v and of course I need to get this thing of the mains. That's where my questions actually starts. I've read tons of forum posts, instructions and watched a lot of videos about making a 12v battery pack but I'm confused with all that information. From what I've read 18650 Lithium-Ion batteries have an excellent power density and would suit my system best (small enclosure and portable). But of course I'm open for new ideas anytime. I planed to make the power pack out of 4s3p 18650's from an old laptop battery (don't have the exact data of them yet). So the pack would provide about 8Ah at 14.8V nominal. With a step down converter to 12v it't could power the amp and for the bluetooth I would use a car usb adapter to get the 5v needed. So far so good, but regarding the power pack I have a few questions. 1. Would a 3s4p (11.1V) arrangement be good enough to power the 12v amp since the 11.1V are in average right? 2. The biggest question I have is - How to charge that thing? As I want to have it as portable as possible, to be able to charge it anywhere from a normal power socket would be ideal. I know there are dedicated chargers for lithium batteries but they are quite expansive and not really handy to carry around. Is there any other solution to handle that? 3. BMS, PCB - I'm confused. From what I've read, to charge multiple cells they have to be in balance right? An over-charging and over-discharging can lead to fire/explosions and to prevent that a BMS is essential right? But first - how do i connect that BMS? Only to each of the parallel strings or to every single cell? Second, is it possible to use that BMS to charge the pack? Maybe also in balance? 4. For the case that the 18650 from the laptop battery are undercharged, where is limit to withdraw them and to charge them to balance with a TP4065 at 1A? That's it for now. Sorry for the long text and thank you for reading through it. I read so much on the net but didn't find the right answer for me.

I have got 4 3.7v 6000mAh lithium ion batteries connected in series with 2 batteries holders. I would like to charge them without taking them out (prefer to seal a unit). Anyone know how to do this (I could connect the 4 "cells" individually to separate input/outputs.)? Also have 19v 3.16A power supply available to use also for charging (Batteries are for making it portable and plug for the 19v) Have this ordered if it is useful: 4-Cell Li-ion Li-Po Lithium Battery 18650 Charger Protection Board Help appreciated

I have several questions. But the basic idea is that I want to extend the runtime of a device (such as a cell phone, tablet, camcorder, whatever) by increasing the mah. So here are the things I am wondering: 1)Many lipo batteries have 3 or 4 contacts, one is -, one is +, and the others are typically data or something. can I simply connect additional lipo's (just the + and the -) in parallel with the corresponding contacts in the device? 2) Are there any ill effects of charging (presumably from the built in charger of the device, like a cell phone) and discharging (using the device) parallel lipo's? 3) They will all have the same voltage rating, but do they all have to have the same mah rating? thankyou

I want to make a 4s4p pack out of 18650 cells. I am asking a lot of questions and doing a lot of research online before buying the parts so I know it will all work when I order the parts. My first question is, should I make the pack out of 18650 cells with individual protection or all connected to one PCM? With protected cells all I need to do is connect the charger and the cells will charge and cut off at the right time? This is the charger I want to get. Maybe if I used protected cells I should charge them by taking them out of the pack and charging them in 4x wall chargers like this one. Say I didn't use cells with individual protection. I have my eye on this PCM . It has a balance control function. I can see the benefit of balancing cells in a 4s1p configuration but does balancing work properly in a 4s4p configuration when 4 cells are acting as one? Lastly I want to make the pack user serviceable so I will use battery holders. I saw some here but it would cost over 50 dollars for all the holders. That seems too expensive. Do you know of cheaper ones? Thank you for your input -Jacob